Project Summary To reduce the prevalence of sexual assault on college campuses, colleges and universities are now mandated to implement sexual assault prevention programs that include bystander interventions, which train witnesses to intervene in order to diffuse potentially risky sexual situations. Studies show that bystander training is associated with self-reported attempts to prevent sexual assault; but self-reports are subject to a range of biases due to inaccurate recall or participants? desire to appear to have ?done the right thing.? Thus, the field is currently lacking reliable and valid measures of actual bystander behaviors. With the present project, we will address this need by refining and validating the Bystanders in Sexual Assault Virtual Environments (B- SAVE)?a virtual reality-based tool for assessing bystander behaviors in risky sexual situations. Virtual reality technology allows direct observation, recording, and quantification of users' behaviors in response to life-like scenarios presented in a standardized fashion. The B-SAVE leverages these capabilities by having participants interact with ?friends? in a virtual house party and respond, in an open-ended manner, to a series of interactions reflecting various forms of sexual risk. In the current project, we will refine the B-SAVE (Study 1) and then assess its construct validity (Study 2) using independent samples. We expect that participants will rate the B-SAVE as highly realistic and that responses to the B-SAVE will correspond in predicted ways to measures of several constructs that have been previously linked theoretically and empirically to bystander behaviors. This tool will have a positive translational impact because the B-SAVE can be used to test the efficacy of bystander intervention programs as well as identify novel causes, consequences, and mechanisms of bystander behavior to prevent and disrupt sexual assault.